Manchester United have rejected a second bid from Chelsea for striker Wayne Rooney, the club have confirmed.

Chelsea put forward an offer for the England forward on Sunday, thought to be around £25m plus add-ons that would take the deal towards somewhere near the £30m mark, but it was immediately rejected.

A United spokesman said: "A bid was received yesterday and immediately rejected. Our position remains that he is not for sale."

The second bid and United's swift response will now focus Rooney's mind on his future at Old Trafford – there have been reports that he will consider handing in an official transfer request. The Chelsea manager, José Mourinho, has made the 27-year-old his top transfer target and Rooney told the former United manager Sir Alex Ferguson last season that he wanted a move. Chelsea's goalkeeper Petr Cech has also welcomed the club's pursuit of Rooney.

David Moyes has repeatedly stressed that Rooney is not for sale. The player, however, was unimpressed by the manager's remarks that he would effectively have to be an understudy to Robin van Persie.

Rooney has been left out of the squad to face AIK in a friendly against Stockholm on Tuesday, with Moyes saying: "Wayne hurt his shoulder in a fall during a match on Saturday. It's not too serious and I don't expect it to keep him out for too long. I'm disappointed he's missing the game because we were keen to get him back involved and ready to play."